With headlines circulating about Emerald Ash Borers and Asian Longhorned Beetles, there is definite concern among industry professionals for the health of trees infested with these insects.
The most effective treatment for these pests requires a product with some form of Imidacloprid. In its liquid form this insecticide can be injected into the xylem of the tree and when the insect begins to digest the tissue, its nervous system shuts down, causing it to die, according to Joel Spies, marketing director for Rainbow Treecare Scientific Advancements.
Imidacloprid can be applied four different ways to achieve results, including use in tree and soil injector systems, soil (also known as basal) drench and foliar sprays. For instance, tree injectors employ macro or micro infusion techniques to inject chemicals directly into the tree trunk and show results in about seven to 14 days, while soil injectors shoot chemicals into the tree base for absorption by the root system and can take about two weeks to produce results. Although, experts say, it’s always best if you can avoid wounding the tree with an injection system.
Spies notes that macro infusion tree injectors should be used in more extreme cases to inject a larger amount of chemical agents into the tree, as opposed to micro infusion, which uses significantly less chemicals.
However, Roger Webb, president of TreeTech, says only a specific amount of Imidacloprid is needed to control Emerald Ash Borers as well as Asian Longhorned Beetles. “Bayer’s proprietary research has indicated optimal EAB control is possible with the 6 milliliter dosage,” Webb says.
For soil drenching, landscapers or arborists should dig a shallow trench around the tree base and then pour chemicals around the root collar, according to Rainbow Treecare. This approach doesn’t physically damage a tree, but can take considerably longer to produce results – 30 to 60 days, according to Peter Wild, president of Arborjet.
So, if you need quick results, consider tree injection or foliar or bark sprays. Sprays give results quickly by killing pests on contact. “Drawbacks to this technique are obvious: applicator exposure, chemical drift and difficulty getting equal distribution,” says Jim Zwack, national accounts manager for Rainbow Treecare Scientific Advancements.
“There’s really no one application method that’s going to solve all of your problems,” Spies adds. “But every problem is going to have a use for one or all four of these solutions.”